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Abstract: 3-D Design with Previous HitDMONext Hit Modelling

D. L. Connelly, J. M. Galbraith

The seismic industry applies Previous HitdipNext Hit Previous HitmoveoutNext Hit (Previous HitDMONext Hit) processing increasingly often to correct for the up-Previous HitdipNext Hit reflection point smear inherent in common midpoint (CMP) 3-D seismic surveys. Previous HitDMONext Hit requires a complete reconstruction of a wave field by shifting and summing energy along source-receiver azimuths. To design 3-D surveys we require knowledge of the interaction between 3-D geometry and the effect of Previous HitDMONext Hit on seismic data.

Black and Egan (1988) described a Previous HitDMONext Hit filtering correction to correct a deformed flat event to uniformity for 2-D data with irregular geometry. Beasley (1993) proposed a technique to "count" the dips in Previous HitdipNext Hit-azimuth bins to assess the uniformity of offset-Previous HitdipNext Hit-azimuth distributions and a new set of attributes to consider during 3-D design. Beasley and Klotz (1992) also proposed the use of the flat-Previous HitdipNext Hit "count" multiplicity to correct for the amplitude variations appearing from variation in multiplicity on an implied signal and random noise model. Both techniques show great promise for future applications.

In this paper, we propose a more empirical, and therefore direct, method to determine the appropriateness of a particular 3-D geometry for Previous HitDMONext Hit processing.

Given a dipping geologic event at a specified CMP position and at a specified time, we compute the input event times and OMP positions to model the Previous HitDMONext Hit process. Thus, assuming that every CMP in the survey contains such a "pseudo" dipping event we produce the Previous HitDMONext Hit response at every CMP position in the survey. Our process produces an estimate of the Previous HitDMONext Hit response (and a possible Previous HitDMOTop correction filter) for a particular survey geometry to a specified event (either flat or dipping).

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela